Eye II Flashcards
What is the optic disc?
Site where the optic nerve joins the retina
What does the fovea centralis contain?
Cones
What is the point on the retina where it is liable to detach?
The RPE
What is the area that sits right above the choroid in the retina?
RPE
What is the function of the RPE?
Control the release/absorption of metabolites from the choroid
What are the four groups of cells in the retina?
- photoreceptors
- conducting neurons
- association and other neurons
- Supporting cells
True or false: the cones and rods directly synapse with the optic nerve
False–they synapse with bipolar cells
Where are the ganglion for the rods and cones located?
On the surface of the retina (faces vitreous humor).
What is the neural pathway from the cones to the optic nerve?
- rods/cones
- bipolar cells
- ganglion
- Optic nerve
What are the three types of supporting cells of the retina? What are each of their functions?
Muller’s - diffuse nutrients to rods and cones
Microglial -cleaner
Astrocytes - cleaner
What type of epithelium is in the RPE? What does it contain?
Simple cuboidal
Melanin
Where is the RPE in the retina (relation to other layers)?
Sits on top of Bruch’s membrane
What are the four functions of the RPE?
- Light absorption
- Blood-retina barrier
- Restore photosensitivity
- Dispose of membranous discs
What are the ten layers of the retina, starting at the choroid?
- RPE
- Layer of rods and cones
- Outer limiting membrane
- Outer nuclear layer
- Outer plexiform layer
- Inner nuclear layer
- Inner plexiform layer
- Ganglion cell layer
- Layer of optic nerve
- Inner limiting membrane
What is the first layer of the retina (above the choroid)?
RPE
What type of epithelial cells are in the RPE? What specializations do they have? What are these used for?
Simple cuboidal with microvilli, that mesh with the rods and cones, as well as melanin
What is the second layer of the retina, above the RPE?
Layer of rods and cones
What is in the inner segment of rods and cones?
Mitochondria, golgi
Where are the photosensitive discs in rons and cones?
In the outer segment of rods/cones, close to the RPE
What are more numerous: rods or cones?
Rods
What is retinal?
Vitamin A
What is the chemical changes that takes place in rods? What is the key chemical produced?
Retinal to retinol
Rodoxin
What are the packing cells that pack around rods and cones, and provides support?
Muller cells
Light induces what change in rods and cones?
Hyperpolarization (NOT depolarization)
What is different about the plasma membrane of cones compared to rods?
It is not continuous in cones
The apical part of the Muller cells form what histological structure?
The outer limiting layer
What is the third layer of the retina?
The outer limiting membrane
What is the fourth layer of retina?
Cell bodies of rods and cones
What layer sits above the cell bodies of rods and cones? What does it contain?
The outerplexiform layer, composed of the synapses between the rods and cones, and the bipolar cells
How many bipolar neurons synapse with rods? Cones?
100s for rods, 1 for cones